1. Field of the Invention
The present invention relates to a battery-powered radio receiver, and more particularly to a receiver and a battery-saving method-used in a selective calling system.
2. Description of the Related Art
A selective calling receiver has been widely used for various purposes Sine such a receiver is battery-powered and usually taken on the road, needless to say, it is better to work as long a s possible without changing a battery. From this point of view, there have been proposed various battery-saving techniques.
As disclosed in Japanese Patent Laid-open Publication Nos. 62-38625, 1-19660, and 3-67371, conventional receivers have employed an intermittent receiving method such that power is supplied to a radio system only when a group addressed to the receiver itself is received. Since the radio system incorporating a radio receiver consumes a relatively large power, the intermittent receiving method causes its power consumption to be reduced efficiently. In the above-mentioned receivers, the intermittent receiving function is activated only when its power switch is in the ON position and is fully deactivated when the power switch is turned off.
When a user returns to his office or home, however, the selective calling receiver is usually powered off not to consume the battery and may be left alone. Then the user frequently forgets where it is located. Since the intermittent receiving function is fully deactivated when powered off, the receiver remains silent even when a calling signal is being received.
Therefore, it is hard to look for the receiver in a bag or a room. Since a selective calling receiver has been formed recently with enhanced portability, the use has increased difficulty in searching for such a small receiver.